Plume neutralization of an ionic liquid electrospray thruster: better insights from particle-in-cell modelling

Zhang, Baiyi; Cai, Guobiao; He, Bijiao; Zhang, Kai; Zheng, Hongru; Wang, Weizong

doi:10.1088/1361-6595/ac3e7f

Cited by 6 publications

(4 citation statements)

References 43 publications

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“…The coupling of these oscillations has significant impact on the performance of the RF biased system, such as the periodic change of thrust in figure 8. Similar phenomena of plasma oscillations are also observed in the alternate extracted beam of oppositely charged ions of a gridded iodine ion thruster [28] and plume neutralization of an ionic liquid electrospray thruster [55]. In the alternative extracted beam, the ion density and plasma potential distribution in phase space indicate typical oscillations of the charged ions due to the periodically alternating extraction and acceleration of oppositely charged ions.…”

Section: Electron Energysupporting

confidence: 60%

Radio-frequency biasing of ion acceleration grids with different propellants

Tang

Cai

et al. 2022

Plasma Sources Sci. Technol.

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In order to ensure the space charge compensation of the plume, conventional ion thrusters need an additional neutralizer to release electrons. When a radio-frequency (RF) voltage is applied across the grid system instead of a direct-current (DC) voltage, the simultaneous extraction of ions and electrons is achieved, thereby a neutralizer is not required. In this paper, based on the non-uniform distribution of neutral gas density calculated using the angular coefficient method, the particle-in-cell Monte Carlo collision (PIC-MCC) method is used to thoroughly investigate the spatial and temporal dynamics of particles and the grid system performance for different propellants (argon, krypton and xenon) in such an RF grid system. RPA and E×B probe are employed to measure the IFDFs of RF ion thruster with RF biasing, which are used to compare with the simulations. The simulated linear relationship between the self-bias voltage and the RF voltage amplitude and the multi-peak behavior of ion flux distribution function (IFDF) under low RF frequency conditions are comparable with the experimental data. The simulated IFDFs compare well with the experiments with the deviation of energy peak position less than 7% and 10% from those by RPA and E×B probe respectively, indicating the effectiveness of the used model. Simulations show the RF grid system is able to realize the extraction of electrons for all three propellants, so as to achieve the plume neutralization without an external neutralizer through the spatial and temporal oscillations of the beams. Electrons pass through the grid twice (extracted from the upstream, and backflow from the downstream), bringing two peaks of electron current to the accelerator grid in one period. The thrust-RF voltage curves for all three propellants show obvious slope transition, when the perveance limit is reached. The low-energy ions in the plume are mainly generated by the electron impact ionization processes for Xe while by CEX collisions for Ar. A larger ion current density of Xe on the downstream surface of the accelerator grid, which may lead to possibly more serious erosions of grids, is found compared with those of Kr and Ar. This is mainly contributed by the larger density of electron impact ionization generated ions of Xe in the downstream because Xe propellant has a larger electron density and ionization cross-section.

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Section: Electron Energysupporting

confidence: 60%

Radio-frequency biasing of ion acceleration grids with different propellants

Tang

Cai

et al. 2022

Plasma Sources Sci. Technol.

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“…Wang et al [32][33][34] performed Particle-in-Cell (PIC) simulations to investigate the plume in spatial distribution and found that the bipolar ion beam was almost uncoupled, and the plume exhibited no backflow. Zhang et al [35] conducted PIC simulations of the plume in spatial distribution and observed that self-neutralization of the plume is achieved through temporal and spatial oscillations of the ion beam. The spatial distribution of the plume demonstrates strong self-neutralization effectiveness and is relatively easier to achieve compared to temporal distribution.…”

Section: Introductionmentioning

confidence: 99%

“…Researchers describe the self-neutralization effectiveness of plumes mainly by comparing the potential and electric field strength at specific points or lines in space, however, there is a lack of a precise definition of the self-neutralization effectiveness of the plume. Wang and Zhang et al compared the spatial electrode potentials of bipolar and unipolar plumes by examining cross-sections in various x or y directions [32,35]. On the other hand, Oudini recorded the charging effect of the plume at a specific point located 5 cm downstream in the 50 × 5 cm space [36].…”

Section: Introductionmentioning

confidence: 99%

Study on the plume self-neutralization of ionic liquid electrospray thruster based on median potential

Du,

Wu,

et al. 2024

Plasma Sources Sci. Technol.

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Ionic liquid electrospray thruster (ILET) has the advantages of high specific impulse, precise thrust control, and low structural mass, which make it ideal for small satellites. The charged particles of ILET’s plume may lead to device charging or even damage, restricting its engineering applications. Thus, this paper examines the self-neutralization effectiveness of the ILET's plume under various emission conditions using particle-in-cell simulations. In order to accurately evaluate the self-neutralization effectiveness of the ILET’s plume, the median potential is explained in this paper and its reasonableness as the evaluation criterion for self-neutralization of the plume is verified. The working envelope for achieving self-neutralization of the ILET’s plume is determined by simulating the bipolar plume under various emission conditions. The results indicate that when the highest and lowest potentials are the same, the mean electric field strength between two points in space with a better degree of neutrality is 200% higher compared to points with a lesser degree of neutrality. The study determines the working envelope to realize self-neutralization of the ILET’s plume with an effectiveness of 70%. When the emission voltage of the anode thruster is fixed, the range of the cathode thruster’s voltage ranges from 108.36 V to 228.74 V. The asymmetry between the anode and cathode emissions of the ILET prototype significantly influences the operational range of the cathode thruster. Greater asymmetry leads to a narrower operating range for the ILET to achieve self-neutralization of the plume. This study serves as a guide for the ILET to achieve self-neutralization of the plume.

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“…It plays a significant role in various problems, such as plasma plume expansion [2,3], particle-beam interactions [4], plasma instabilities [5,6], and inertial electrostatic confinement fusion [7]. Many types of simulation methods for solving the Vlasov-Poisson equation have been developed, such as the fully kinetic particle-in-cell (PIC) method [8][9][10][11][12], the semi-Lagrangian method [13][14][15][16], and the Eulerian method [17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Physics-informed neural networks for solving forward and inverse Vlasov–Poisson equation via fully kinetic simulation

Zhang,

Cai,

Weng

et al. 2023

Mach. Learn.: Sci. Technol.

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The Vlasov-Poisson equation is one of the most fundamental models in plasma physics. It has been widely used in areas such as confined plasmas in thermonuclear research and space plasmas in planetary magnetospheres. In this study, we explore the feasibility of the physics-informed neural networks for solving forward and inverse Vlasov-Poisson equation (PINN-Vlasov). The PINN-Vlasov method employs a multilayer perceptron (MLP) to represent the solution of the Vlasov-Poisson equation. The training dataset comprises the randomly sampled time, space, and velocity coordinates and the corresponding distribution function. We generate training data using the fully kinetic PIC simulation rather than the analytical solution to the Vlasov-Poisson equation to eliminate the correlation between data and equations. The Vlasov equation and Poisson equation are concurrently integrated into the PINN-Vlasov framework using automatic differentiation and the trapezoidal rule, respectively. By minimizing the residuals between the reconstructed distribution function and labeled data, and the physically constrained residuals of the Vlasov-Poisson equation, the PINN-Vlasov method is capable of dealing with both forward and inverse problems. For forward problems, the PINN-Vlasov method can solve the Vlasov-Poisson equation with given initial and boundary conditions. For inverse problems, the completely unknown electric field and equation coefficients can be predicted with the PINN-Vlasov method using little particle distribution data.

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Plume neutralization of an ionic liquid electrospray thruster: better insights from particle-in-cell modelling

Cited by 6 publications

References 43 publications

Radio-frequency biasing of ion acceleration grids with different propellants

Radio-frequency biasing of ion acceleration grids with different propellants

Study on the plume self-neutralization of ionic liquid electrospray thruster based on median potential

Physics-informed neural networks for solving forward and inverse Vlasov–Poisson equation via fully kinetic simulation

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